Thursday 5 January 2012 18.30 EST
First published on Thursday 5 January 2012 18.30 EST

Health concerns outweigh any economic benefits of raising the speed limit on motorways, according to an online report in the British Medical Journal.

Increasing the limit from 70mph to 80mph is being considered by the government.

The authors say a higher limit could increase gas emissions and air pollution and could lead to increased obesity, with more people taking advantage of shorter car journeys. Higher speed limits introduced in the US in 1995 resulted in a 16.6% increase in deaths owing to vehicle accidents, say the authors, describing the proposal as a "populist gimmick" by the government.

Given the recent seven-death M5 crash, the report challenged the government to produce the evidence to justify its policy "with its attendant risks to life".